feat: check if the running process is of the same user

When running SafeEyes in multi-user environments (multiple users running
SafeEyes in the same machine), it refuses to start more than two
instances of SafeEyes because it is already running accoding to ps.

This patch adds a check to the running SafeEyes pid such that the
_running() function returns True only if it is running as the same user.

safeeyes/__main__.py

@@ -41,6 +41,7 @@ def __running():
     Check if SafeEyes is already running.
     """
     process_count = 0
+    current_user = psutil.Process().username()
     for proc in psutil.process_iter():
         if not proc.cmdline:
             continue
@@ -53,9 +54,10 @@ def __running():
                 # In older versions cmdline was a list object
                 cmd_line = proc.cmdline
             if ('python3' in cmd_line[0] or 'python' in cmd_line[0]) and ('safeeyes' in cmd_line[1] or 'safeeyes' in cmd_line):
-                process_count += 1
-                if process_count > 1:
-                    return True
+                if proc.username() == current_user:
+                    process_count += 1
+                    if process_count > 1:
+                        return True
 
         # Ignore if process does not exist or does not have command line args
         except (IndexError, psutil.NoSuchProcess):